ubergeeknz:BTR: when driving on long trips, the difference between driving at 100 and 100 is roughly only 5 minutes.
You've discovered a fold in the space-time continuum!
In all seriousness though, it makes a few minutes difference on a long trip. These days I have come to accept this, and only overtake when it is safe and I can do so at a reasonable speed. I do this mostly so I can enjoy the drive rather than being stuck behind someone and constantly having to mind my following distance.
It never fails to amuse me and anger me when I am overtaken dangerously/stupidly by some numpty to stop a short time later at a town further up the road and who should be there, yep the numpty.